Ipod Touch 4 won't charge or sync on computer

Ipod won't charge or sync on computer, but will charge in wall. I replaced the cord. Thought it was USB port, but other things work in them. When I plugged in, I went to Itunes to try to manually sync, but it doesn't show the ipod is connected from there. I cleaned out the connector of the ipod a little, although it didn't look bad. This ipod is been pretty babied, with no trauma ever occurring to it. I was having computer issues before this started, so I thought after I had to remove a virus, that maybe there is some sort of internal change that has occurred that I need to reverse, but don't know of anything. I deleted Itunes and downloaded again and nothing new. Also, plugged into my PC and it did sync, but took everything off, but what I purchased through Itunes. So, from what I think, it must be some sort of setting on my laptop. Right?